"Similarly for sceptics, our results might be seen as proof that placentophagy doesn't 'really work' because we did not find the type of clear, robust differences in maternal hormone levels or postpartum mood between the placenta group and placebo group that these types of studies are designed to detect."

The study provides no clear evidence of benefits compared to a placebo, which is the scientific standard.

But it does show that the practice is capable of influencing maternal hormone levels and that could provide some kind of therapeutic effect.

To what extent, however, is unclear, and more research is needed in order to explore these effects more fully, the team concluded.

Dr Sharon Young, lead author of the study and programme manager for UNLV's Office of Undergraduate Research, said: "While the study doesn't provide firm support for or against the claims about the benefits of placentophagy, it does shed light on this much debated topic by providing the first results from a clinical trial specifically testing the impact of placenta supplements on postpartum hormones, mood, and energy.

"What we have uncovered are interesting areas for future exploration, such as small impacts on hormone levels for women taking placenta capsules, and small improvements in mood and fatigue in the placenta group."